Blasting cap



I. STEERS Dec. 9, 1924- BLASTING CM Filed Feb. 16. 1924 ZIIIA /m/ew/of" /[feer:

5)/ /1/.5 Uffa/Hay sra'rss NEWTON I. STEERS, OF WILMINGTON, DELAWARE, ASSIGNOR TO E. I. DU POINT DE NEMOURS 65 COMPANSE` 0F WILMINGTON, DELAWARE, A CORPORATION OF DELA- WARE.

BLASTING CAP.

Application lit-led February 16, 1924.

To all whom t muy concern Be it known that I, NEWTON I. S'rnnns, a citizen of the United States, and a residemL of Wilmington, in the county ot New Castle and State of Delaware, have invented a certain new and useful Blasting Cap, ot' which the following is a specification.

rlhis invention is in the art ot explosives,v and has particular relation to blasting caps, and, strictly, to the shell of such a cap. The shell is loaded with a sensitive and violent explosive, e. g. fulminate ot mercury, and in use a fuse is inserted in the open end ot the loaded shell, or cap, and the cap is placed in close relation to a charge of high explosive to be detonated; the explosion of the cap gives the shock and heat necessary to cause detonationA of the charge. These mat ters are of course well understood in the art; but tor present purposes it is to be noted that upon the explosion the material of the shell becomes mingled with the material being blasted. The present invention has to do with the overcoming of the ditculties which this mingling entails.

Heretofore copper shells have been in almost universal use for blasting caps, since not only is copper readily available and easily drawn but also, and primarily, it is not attacked by the action of the free mercury of the fulminate Yet a great disadvantage of the copper shell is that its iinely divided particles or compounds therefrom contained in the material blasted down cause discoloration of the material, when such material is, say, treated in chemical processes. A notable instance ot' this is in the mining ot fine clays for high-grade pottery: the presence of copper in this clay causes objectionable discoloration of the finished product. Again, owners of soft mines object to the copper. I have devised a blasting cap which overcomes difficulties and faults such as those indicated.

One object of the invention is to provide a blasting cap and shell the particles of which will not have a deleterious etfect on the material blasted, but yet the shell will satisfactorily resist the action of material with which the shell is loaded, e. g. the free mercury in fulminate, and at the same time will be composed of readily available, easily workable and inexpensive materials. To

serial No. 693,204.

this end, and also to improve generally on articles ol the character indicated, the invention consists in the various matters hereinafter described and claimed.

Tithout restricting the invention thereto, I describe the same with more particular reterence to the embodiment thereof illustrated in the accompanying drawing, in which Figure l is an elevational diametrical crosssectional view, and Figure 2 a simple crosssectional view on the line l-l and the line 2 2 of Figures 2 and l, respectively. For simplicity, in Figure l the explosive is but partially shown, and no attempt is made in the figures to accurately indicate the relative thicknesses of the shell proper and the liner.

In accordance with the invention I make the shell with a plurality of walls, as l and 2. Of these, the outer wall is of material of the necessary strength, but, as distinguished from copper, is such that it will not cause discoloration of the blasted materials. For example, it is a metal which will not oxidize readily or whose compounds are not such as will cause discolorations. I have found that aluminum meets these requirements in a highly satisfactory manner; and, too, it is cheaper and lighter than copper, and is readily worked, e. g. drawn. The inner wall 2 is vof a material which will withstand the action of the explosive 3, that is, as a practical matter in present day practice, it is a material which Will withstand the action ot the free mercury in fulminate of mercury, and is also one which will not cause discoloration as aforesaid. Desirably it is ol tin, although it may be ol lead or other suitable material. As is evident, in referring to the inner wall being explosive resistant with standing the action of the explosive, and the like, I have reference to the ability of the wall to withstand the chemical or like attack of the explosive or certain of its ingredients, rather than to ability to withstand the shock of the explosive.

It is to be particularly noted that, as illustrated by the example given aluminum and tin) the invention permits of, and provides for, the selection of a material for the outer wall with primary consideration for its non-discoloring properties and strength, without having to consider its ability to -lll resist the action of the explosive, since this resistance is furnished by the inner Wall; also it provides for the selection ot property resistant material without having to consider its strength. Thus the invention provides a shell which Will not cause discoloration. and yet is of the proper strength and explosive resistant qualities, and, specifically, provides a shell which, While having the desirable features of copper, has not the disadvantages ot copper.

Desirably, and as conventionally shown, the major'portion of the Yshell is provided by the relatively thick strengtlii-giving Wall l, While the resistant Wall 2 may be but relatively thin, havingv the character of a liner. For example, in a shell 1.5 inches long` and having; an outside vdiameter of .274: inch and an inside diameter of .220 inch, the aluminum outer Wall may be .O20 inch thick and the tin liner .00T inch.

The shell can be made in any desired Way. For example, if both the inner land the outer shell are of ductile metal they may be drawn together. Or the shells may be made separately and thel inner tightly fitted into the outer. Vhile I have made particular reference to aluminum and tin it ivill be under stood that the invention is not restricted thereto. For example, the outer Ashell may be made from metals other than aluminum and having the desired characteristics; and the inner Wall may be made from any metal or combination of metals having' the characteristics desired 'for that Wall, also hard rubber, pyroxylin plastic and similar materials may be used.

The shell may be also made from a sheet of aluminum which .has been tin plated o1 trom other plated metals.

I claim:

l. A blasting' Vcap shell comprising` a st.rengthimparting Wall of strong non-dis coloring` material, and an inner explosivecontacting wall of non-discoloring material of a character to withstand the action of the explosive to be received in said shell.

2. A blasting cap shell comprising a pair of shell units the one received Within the other to form a liner for su l1 other, the units being of non-discoloring materials, and that or' the liner being explosive-resistant.

3. A blasting cap shell comprising a plurality of Walls of non-discoloring material, the material of the inner Wall beingsuch as to withstand the action ot the liree mercury iu t'ulminate.

a. A blasting` Cap shell o't' non-discoloring materials having a laminated wall, the inner lamination of the Wall being of a character to withstand the action ot' the explosive to be received in said shell.

5. A non-discoloring blasting, cap shell ot laminated structure, the inner surface of the shell being of a Vcharacter to withstand the action of the explosive to be received iu said shell.

6. A blasting cap shell comprisingan iuner explosive-contacting Wall of tin and a surrounding Wall or' alun'iinum.

7. A blasting `cap comprising a shell and explosive received in said shell, said shell comprising a strength-imparting wall ot strongnon-discloring material, and an inner Wall of non-diseoloriugn'iaterial ot a charaeter to withstand the action ot said explosive.

8. A blasting' cap comprising an outer Wall of aluminum, a liner of tin `for said Wall, and a charge of mercury fulminate in the shell and separated from said outer wall by said liner. y

In testimony whereof I -atlix my signature.

NEVTON I. STEERS.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,518,611, granted December 9, 1924, upon the application of Newton I. Steers, of Vilmington, Delaware, for an improvement in Blasting Caps, an error appears n the printed specification requiring correction as follows: Page 1, line 41, for the word sot't read Salt; and that the said Letters Patent should he read Wit-h this correction therein that the same may conform to the record of the vcase in the Patent Oflice.

Signed and sealed this 6th day of January, A. D. 1925.

[SEAL KARL FENNING,

Afffz'nf/ ofmmissz'oner 0f Patents.

Certificate of Correction.

that in Letters Potent No. 1,518,611, granted December 9` ion of Newton 1. Steers, of lVilmingtonv` Delaware, for on an error appears in the printed specification requiring correction as follows: Page 1v` line 41, for the word soft rend Srl/Zi: and that the said Letters Patent shonlcl he read with this correction therein that the saine may conform to the record of the Case in the Patent Oflice.

Signed and sealed this 6th clay of January, A. D. 1925.

KARL FENNING,

[sEAL.`l

Affi/zg (7m/11217355011er of Patents.

It is hereby certified 19241, upon the applieat improvement in Blasting Cops,7 

